I would recommend chad's videos. That is basically all I used for organic chemistry. After that, I would do some practice problems in Kaplan. At times when I got a problem wrong I thought, "hey, Chad didn't teach me this!" I would then refer to my organic chem notes from Chad's videos and find the reaction there. It was like they magically appeared! haha...I would say that as long as you memorize all the reactions from Chad's video notes, you should be fine. Of course, the OAT does spring some surprising questions on you sometimes. For example, they might talk about specific tests that make things change certain colors. But there aren't many of those problems, so I wouldn't worry about those. Good luck!